<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let radius=prompt('请输入圆的半径')
        let round=2*3.14*radius
        let area=3.14*radius*radius
        document.write(`<h1>半径:${radius}</h1>
        <h1>周长：${round}</h1>
        <h1>面积：${area}</h1>
        `)
    </script>
</body>
</html>